1. Field of the Invention
This invention relates to a continuous furnace (once-through furnace) for heating glass panes to their bending and/or toughening temperature, comprising a hot gas support bed and comprising an entraining apparatus, acting upon the edges of the panes, for conveying the glass panes over the hot gas support bed from a feed station to a discharge or transfer station. The invention furthermore relates to a bending and toughening installation for glass panes comprising a furnace of this type.
2. Description of the Related Art
In the known continuous furnaces comprising a hot gas support bed (e.g. U.S. Pat. No. 3,223,501), the plane hot gas support bed is of linear form and is slightly inclined to the horizontal, transversely to the conveying direction of the glass panes. As entraining devices for the glass panes, driven entraining rollers having their axes of rotation perpendicular to the plane of the support bed are disposed along the lower longitudinal edge of this bed. The glass panes bear with one longitudinal edge, as a result of the force components acting in the direction of slope of the conveying plane due to their weight and the floating arrangement on the support bed, against the entraining rollers and are conveyed onwards by frictional engagement with these rollers. The glass panes are laid on the hot gas support bed or transferred from conveying rollers onto the hot gas support bed at one end of the furnace. The discharge or transfer of the heated glass panes from the hot gas support bed takes place at the other end of the rectilinear furnace, that is to say at a more or less large distance from the charging point of the furnace.
For a continuous furnace for glass panes, even if the furnace is fully automated, the feed station and discharge station of the furnace must be continually monitored. A linear continuous furnace has, however, a comparatively large length, and the feed and discharge stations are consequently so far apart that a separate monitoring person or operator is necessary for monitoring each of these two stations.